The subject matter herein relates generally to electrical components and methods of manufacturing electrical components.
Electrical components, such as circuit boards and antennas are typically made by a subtractive process, where a copper sheet is applied to the substrate and a portion of the copper sheet is etched away to create the necessary circuit traces. Such a process is referred to as a subtractive process because copper is removed from the copper sheet applied to the substrate via etching or machining to achieve the circuit trace geometry. Typically, a solder mask is placed on top of the traces. Circuit boards manufactured by a subtractive process are not without disadvantages. For instance, every time a new geometry or circuit is required, a photo-resist etch plate needs to be created. This requires time and money investment before the circuit geometry can be made.
Some circuit boards manufacturing processes have been developed that use an additive process where a seed layer of conductive ink is deposited on a substrate and the seed layer is plated. The plating may be performed by either an electroless plating process or by an electroplating process. Both processes have drawbacks and create problems.
Electroless copper plating has a slow deposition rate. Another problem with electroless copper plating is that such plating is typically performed in a bath having a high pH, which degrades the binder in the conductive ink of the seed layer, which results in a reduction in the adhesion of the seed ink to the substrate and consequently the adhesion of the circuit to the substrate. Degradation is exacerbated by the low deposition rates, which require the circuit board to be immersed in the bath for a long period of time.
Electrolytic plating is an acid-based process which does not degrade the ink and is quicker than electroless plating, however electrolytic plating introduces its own problems. For example, electrolytic plating requires an electrical contact with the seed layer to provide a path for the electrical current needed for plating. The contact can be an auxiliary conductor that brings the current from the circuit pattern to an edge of the circuit board. Such auxiliary conductors may be problematic to the operation of the component. For example, for an antenna, the auxiliary conductor affects the antenna properties of the designed antenna pattern. In such cases, the auxiliary conductor needs to be removed, which is difficult. Additionally, with electroplating, the terminal effect results in the plated deposit building thicker and more quickly in the region nearest the auxiliary conductor. The buildup affects the edges of the pattern as well as the thickness, which can result in changes in the intended spacing of the conductors of the circuit and can affect antenna performance.
A need remains for an electrical component that can be manufactured by an additive process quickly and without the problems of conductor adhesion to the substrate.